There is provided a personal computer comprising a recording medium reproducer such as a CD-ROM drive or a DVD (Digital Video Disc) drive. This type of recording medium reproducer is utilized for obtaining data for the computer. In recent years, however, it has been also used for reproducing a music CD, for example.
However, the conventional personal computer reproduces the music CD using application software run on an OS (Operating System) of a main CPU. Therefore, a circuit required for the personal computer to perform normal processing enters an approximately full-active state even at the time of mere music reproduction. Further, the main CPU must be booted up. Therefore, an initial set time period is required from the time when the main power supply is turned on until actual reproduction of music data is started.
JP-A-9-101848 discloses a small-sized multimedia information processing apparatus provided with a mode switch functioning exclusively as a CD player. The processing apparatus is so constructed that diagnosis and initialization processing for functioning as a personal computer are omitted to the utmost when the switch is turned on, and a device driver is started from a ROM. The apparatus stops the supply of power to a hard disk device or the like which is not required to reproduce a music CD when the mode switch is turned on.
In the conventional apparatus, however, the CPU performs light processing or inherent processing by turning the mode switch on or off. In either case, processing is performed by the CPU. When the music CD is reproduced in a state where the CPU enters a stop mode (an idle mode or a sleep mode) after it is booted up as an inherent personal computer, for example, therefore, the CPU becomes active again by releasing the stop mode.